eChapters

1. Introduction

Bamboo has historically been an integral part of human culture. Bamboo is a mystical plant representing symbol of strength, flexibility, tenacity, endurance and compromise. Throughout Asia, bamboo has for centuries been integral to religions, ceremonies, art, music and daily life. Bamboo provides numerous environmental benefits such as playing a critical role in the balance of oxygen/carbon dioxide in the atmosphere. Bamboo is the fastest growing canopy for the regreening of degraded areas and generates more oxygen than equivalent ultraviolet rays. It is an atmospheric and soil purifier. Its soil conservation properties create an effective watershed, stitching the soil together along fragile river banks, deforested areas, and in places prone to earthquakes and land slides. Its fast growing and high yield nature makes it a highly valued renewable resource. Its low cost and abundance call for its utilization to a full extent. 

1. Introduction

There is intense commercial interest in dehydrated fruit and vegetable products especially mango powder, banana powder, orange powder, papaya cereal flakes to powder, tomato juice powder and other vegetable powders, which are in great demand for soups, biscuit type cookies supplemented with fruit powders (Ana Maria et al. 2009; Sunita and Chauhan 2008), pizza mixes and sauces. Natural fruit and vegetable powders are gaining lot of popularity in recent years as they are very easy to handle after production, require minimum storage space and they are attractive. Tamarind powder is developed from tamarind fruit (Tamarindus indica) (Manjunath et al. 1991) and recently cashew apple and guava residues from fruit juice industry were successfully converted into fruit powders and used at different levels of wheat flour substitution for cookies formulation (Ana Maria et al.2009) and fruit puree like papaya can be mixed with cereal flour to prepare slurry and after gelatinization, the slurry can be useful for preparing drum dried flakes and powder (Sunita and Chauhan 2008). Tropical fruits are exotic in flavor but their juices and purees are seldom available in dehydrated powder (James, 1971). Citrus juice concentrates were produced during world war II in powdered form by using spray, drum, vacuum-puff, and freeze drying (USDA, 1962). The preservation of fruits and vegetables by dehydration offers a unique method, which may be considered as an alternative low cost preservation technique. A shift from fresh to more and more processed foods with significant value addition is bound to occur sooner or later considering the socio-economic changes taking place in the country and the rapid integration of Indian economy with global system. Most popular brands are found in the “ready to consume” food sector.

1. Introduction

Intermediate moisture foods are semi moist foods that have some of their water bound by glycerol, sorbitol, salt or certain organic acids, thus preventing the growth of many microorganisms (Stewart et al. 2001). It is now well recognized that fruits and vegetables are dehydrated to an intermediate moisture level (20-50%) (Stewart et al. 2001; Purvi et al. 2003). As the intermediate moisture products are characterized by a semi moist consistency so these foods have enough moisture content to permit easy chewing but low enough water content to prevent spoilage production of intermediate moisture foods is based on an increased scientific understanding of the chemical reactions involved in traditional food preservation methods (Purvi et al. 2003).
There will be better retention of original flavor and texture compared to fully dried products, with concomitant reduction in bulk, weight and cost of packaging, transportation and storage. Such intermediate moisture foods are more appropriate for developing countries in view of their minimal processing requirements, stability under ambient conditions, safety, convenience, ease of nutrient content adjustment, energy savings and low capital investment. They are also eminently more suited than dehydrated or canned foods for military rations (FAO, 2005).

1. Introduction

Pulpy and juicy fruits like orange, guava, banana, grape, mango, papaya, pears, apples and jackfruit can be converted into fruit products like squashes, juices, cordials and ready-to-serve (RTS) fruit beverages. These RTS fruit beverages are both refreshing and thirst quenching and have become very popular. Liquid fruits are the clarified juices prepared from these pulpy and juicy fruits. There is a demand for liquid fruits in the international market for various applications. The liquid fruits can be used as a natural alternative to synthetic beverages. They can be suitably concentrated or diluted, blended with other juices and also can be carbonated as fruit based soft drinks. Removals of pulpy material from the juices make them easier to preserve by pasteurization and are amenable to carbonation. Pulpy fruits can be successfully processed into liquid fruits (clarified juices) by using pectic enzymes. The emphasis of the fruit juice processing industry has, so far, been mainly on conventional clarification processes like enzymatic and chemical treatments followed by filtration using filter aids; and concentration by vacuum evaporation.

1. Introduction

In this era of genomics, proteomics and metabolomics the challenge in nutritional science is to clarify human nutrient requirements and design nutritional strategies to promote health and functional longevity. Our ancient Indian belief that ‘we are what we ate’ and our future health as individuals may well depend upon what we eat today. Plant-based dietary antioxidants are believed to have an important role in the maintenance of human health because our endogenous antioxidants provide insufficient protection against the constant and unavoidable challenge of reactive oxygen species (ROS). We have various endogenous defense chemicals but they are inadequate to prevent oxidative damage that makes human system prone to various degenerative diseases. Hence, it is necessary for increased intake of dietary nutraceuticals that may help maintain the balance between oxidants and antioxidants, slow age-related changes, and prevent onset of degenerative diseases.

1. Introduction

At present there is an increasing demand for colourants from natural sources. Since there is a possibility of banning of synthetic colours in view of their carcinogenic properties and already a reduction in number of permitted synthetic colours from 13 to 8 numbers in our legislation (PFA, 2005), the demand for natural colours is evident. In Japan and European countries because of the green movement, the demand for synthetic colours has been reduced. Synthetic colours in global market account for 400 million dollars. Despite processing limitations and higher costs, the global market for natural colours is estimated to be more than 939 million dollars (Espszezola, 1998). Color is recognized as a major factor affecting food acceptance. The consumer expects a specific food to possess a well defined colour and rejects any appreciable deviation from the normal. The change in colour during the preparation of food is a useful guide to quality control and is used by many food processors as the criterion for selecting raw materials. The characteristic colour of raw food is due to the natural pigments present in the plant and animal material. These can be enhanced in processed food products through the addition of food colourants. Addition of colour can make up for the colour losses during processing. Some of the major groups of colours are anthocyanins, carotenoids, betalains, chlorophylls, flavones and chalcones. Some of the plant sources of pigments are kokum, roscelle, chilli, marigold, beetroot, grapes and safflower. Sources of natural colours can be plants, animals or microbes. Fruits and vegetables form one of the main plant sources of pigments. Some of the plant materials rich in colours viz., alfalfa, marigold, safflower, strawberry, aronia fruits, grapes, red cherries have been exploited for pigment extraction and the results have shown positive effects. Some of the interesting features of the work carried out by researchers in this area are presented in the following sections.

1. Introduction

Pectin is a polysaccharide present in the middle lamella of plant cell walls. The firmness and structure of the plant tissue are attributed to the presence of pectin in the middle lamella. The insoluble form of pectin is called protopectin and the soluble form is called soluble pectin (Kertez, 1951). Protopectin is abundant in green fruits and contributes to hardness of cell, where as soluble pectin is responsible for viscous nature of juice and pulp. Conversion of protopectin to soluble pectin results in loosening of the bonds between the cells and softening of the fruit tissues. Protopectin is reported to be hydrolyzed to pectin by enzyme action during ripening. Protopectin on restricted hydrolysis yields pectin or pectinic acid. Braconnot (1825) discovered pectin as the gelatinous principle of fruits.

1. Introduction

Food is processed for its preservation, hygienization or value addition. To date, the food preservation technologies such as canning, dehydration, freezing, pasteurization and controlled atmosphere and modified atmosphere packaging have been the main processes employed to preserve foods, with the use of antimicrobials and microwaves also being employed more recently. In future, however, technologies such as exposure to ionizing radiation, high pressure processing, ohmic heating and pulsed electric field processing, could potentially be the new alternatives to the above food preservation technologies.

Irradiation of food involves the exposing of food, either in prepacked form or as such to controlled doses of ionizing radiation being generated either by electrically driven machines such as electron beam accelerators, x-rays or gamma rays produced by radioactive isotopes such as CS-137,CO-60, to achieve certain desirable objectives. The process of exposing a range of food stuffs to specific doses of ionizing radiation is being used to extend the shelf life of food stuffs, to improve their overall safety and quality by eliminating pathogenic bacteria, by reducing number of food spoilage organisms, to reduce the bacterial load on herbs and spices and thereby making them safe to incorporate into food stuffs, to inhibit sprouting in stored tuber and bulb crops such as potatoes, onions and garlic, to disinfest grains, grain products and tropical fruits to prevent damage to the commodity and to meet the quarantine regulations(Arun Sharma, 2004, Farkas, 2006).

1. Introduction

Vegetables and fruits are the next in demand for human consumption after rice and wheat, in all parts of the globe. Fresh fruits & vegetables and their value added products are increasing in popularity day by day almost in all the countries, because of their richness in dietary fibre, minerals & vitamin contents and for their medicinal properties. Maintaining agricultural produce quality and its evaluation are thus naturally important. Decisions concerning maturity and ripeness of fruits and vegetables are based mostly on visual inspections, which are subjective in nature. The quality of fruits and vegetables is mostly decided on the basis of size, shape, colour, gloss, flavour, firmness, texture, taste and freedom from external as well as internal defects. Internal quality factors such as maturity, sugar content, acidity, oil content and internal defects, however, are difficult to evaluate non-destructively. Methods are needed to better predict the internal quality of fruits and vegetables without their destruction. Recently, there has been an increasing interest in non-destructive methods of quality evaluation, and a considerable amount of effort is being made in this direction. But the real problem is how these methods are to be exploited practically on commercial scales and what are the constraints faced in implementing them.

1. Introduction

Fruits and vegetables represent highly perishable items of agriculture, mainly because of their high water content in fresh form. Their production, yield and management under agriculture is dealt essentially under horticulture. They abound in species and varieties in different geographic regions of the world, influenced by the agro-climatic conditions. Some are endemic and confined to certain geographic regions only. Accordingly, they may be tropical, sub-tropical or temperate, depending on their requirements of temperature for growth and yield.

Materials Required

Record book

Procedure

    1.    Follow the instructions given by the teacher and the factory representative.
    2.    Listen carefully to the explanations of the factory representative
    3.    Observe the functioning of various equipments
    4.    Ask queries wherever not understood properly.
    5.    Note down the observations in your record book  

Observations

    1.    Name and address of the factory or processing unit
    2.    Size of the Unit (Large, Small, Cottage, Home)
    3.    FPO Licence No.    
    4.    List of products manufactured    
    5.    Height of the processing plant    
    6.    Information regarding raw material store, finished product storage    
    7.    List of equipments installed in the factory
    8.    Water supply system     
    9.    Waste disposal system    
    10.    Hygiene in the surroundings    
    11.    Any other

Materials Required

Sensory scoring card, products, pen/ pencil for coding, plain water.

Procedure

    1.    Assign codes to the samples i.e. a, b, c, …… or 1, 2, 3, ….. etc.
    2.    Keep the coded samples randomly (eg. c, f, a, b, d, e) in a row for evaluation
    3.    Start the evaluation of samples one by one. 
    4.    Evaluator should rank the samples on the basis of intensity of a single sensory attribute according to his / her preference.
    5.    Compute the means on the basis of the evaluation of different evaluators (replications).
    6.    List the samples in increasing or decreasing order of preference.

Materials Required

Sensory scoring card, products, pen/pencil for coding, plain water.

Procedure

    1.    Take the given two samples
    2.    Make them three by duplicating/repeating either one of the two
    3.    Assign codes to the samples eg. AAB, ABA, ABB,  BAB etc.
    4.    Ask the evaluators to evaluate the samples for any differences between the 3 on the given Specimen Evaluation Card.
    5.    Find out how many of the evaluators have chosen the odd sample correctly (say it is 16 out of 20 evaluators).
    6.    Now find out the degree of difference in the samples indicated by the evaluators who correctly found the odd sample (Say it is much as per 3, moderate as per 8 and slight as per 5 out of the 16 correct evaluators.).
    7.    Find out how many of the correct evaluators preferred A sample and how many the B sample (say 11 preferred A sample and 5 B sample).
    8.    After going through Annexure II you may conclude that the two samples differed significantly from each other as 16 out of 20 evaluators found the odd sample correct. But, the preference was not significant as it should have been at least 13 out of 16 judges indicating same preference so as to make it significant. So, it may be concluded that the two samples differ significantly but both are acceptable.

Materials Required

Sensory scoring card, products, pen/ pencil for coding, plain water

Procedure

    1.    Assign codes to the samples i.e. a, b, c, …… or 1, 2, 3, ….. etc.
    2.    Keep the coded samples randomly (eg. c, f, a, b, d, e) in a row for evaluation
    3.    Start the evaluation of samples for various sensory attributes one by one. 
    4.    Evaluator should rinse his/ her mouth after each sample so as to avoid overlapping of taste, flavour etc.
    5.    Assign marks from 1-9 based on pleasurable and un pleasurable experiences.
    6.    Compute the means for a particular attribute on the basis of the evaluation of different evaluators (replications).
    7.    Find out the best sample on the basis of highest average scores obtained.

Materials Required

Soxhlet apparatus, petroleum ether, water bath, sample, grinder, weighing balance, filter paper, threads.

Procedure

    1.    Take the given sample and weigh it (A)
    2.    Dry the samples in an oven till there is no more weight loss and weight it (B)
    3.    Grind the sample into powder.
    4.    Place a weighed quantity of sample in filter paper, wrap the paper and tie it tightly with a thread so that no powder comes out of the paper during extraction. 
    5.    Pour approximately 100 ml of anhydrous ether into the bottom flask. Turn the heaters on. Set the temperature at about 40ºC.  
    6.    The ether will evaporate and circulate through the sample and again will come back to the flask. 
    7.    Repeat the process for about 16 – 18 hrs for complete extraction. 
    8.    Remove the sample and evaporate most of the ether from the mixture of crude fat and ether obtained during extraction.
    9.    Evaporate excess of ether from the crude fat sample by evaporation on a water bath. Evaporate till it is free from the fumes of ether. Record the weight (C).

Materials Required

Sample, Liebig condenser, digestion flasks (700-750 ml cap), conical flasks, filtering cloth (thick linen cloth for clear filtration) reagents, muffle furnace, crucibles.

Reagents

    1.    0.255 N Sulphuric acid solution : Dilute 2.5 g (1.36 ml) of concentrated H₂SO₄ to 200 ml. Ensure correct concentration by titration.
    2.    0.313 N Sodium hydroxide solution: 2.504 g NaOH / 200 ml water nearly free from sodium carbonate. Ensure correct concentration by titration.
    3.    Asbestos Chips: gooch grade, medium fibre, acid wash and ignited
    4.    10% Potassium sulphate (K₂SO₄) solution: Dissolve 10 g of Potassium Sulphate (AR) in water and make up to 100 ml.

Materials Required

Spectrophotometer, ethyl alcohol, beakers, pestle and mortar etc. 

Procedure

    1.     Preparation of sample extracts
        a.    Liquids : Centrifuge the juice at 5000 rpm for 4-5 min., and collect the supernatant. For liquid samples prepare a 40 % solution in ethyl alcohol. To 30 ml of the sample add 45 ml of ethyl alcohol and mix thoroughly. Filter through Watman 
No. 1 paper.

        b.    Semi-solid samples: To 15 g of blended sample add 15 ml of distilled water and 45 ml of ethyl alcohol. Mix thoroughly and filter through Watman No. 1 paper.
        c.    Dried products: Extract known quantity of sample (4-6 g) with 100 ml of 60% ethyl alcohol for 12 hrs and filter through Watman No. 1 filter paper.
    2.     Measure the absorbance of the samples at 440 nm for non-enzymatic browning and 400 or 420 nm for measurement of colour.
    3.     Prepare 60% ethyl alcohol solution as blank. Add 30 ml of distilled water to 45 ml of absolute alcohol and use as blank.

Materials Required

Ostwald viscometer, stop watch, sample, distilled water, thermometer.

Procedure

    a.    Take sample and distilled water. Record their temperatures (they should be same for correct estimation). If the temperatures are not same bring both to a specific temperature say 20ºC or the room temperature.
    b.    Clean and dry the Ostwald viscometer properly before use
    c.    Fill the ostwald viscometer with distilled water and record the time taken (T₁) for the a known volume of water to flow through the orifice.
    d.    Empty the viscometer and dry it
    e.    Fill the ostwald viscometer with sample juice or liquid and record the time taken (T₂) for the a known volume of sample to flow through the orifice of the same viscometer.
    f.    Calculate the relative viscosity using the following formula

Materials Required

Specific gravity bottles, weighing balance, sample, pipettes, thermometer, distilled water 

Procedure

    1.    Take the sample and distilled water record their temperatures (they should be same for correct estimation). If the temperatures are not same bring both to 20ºC or the room temperature.
    2.    Clean and dry the specific gravity bottles properly before use.
    3.    Record the tare weight of the specific gravity bottle (T) alongwith the stopper.
    4.    Carefully fill the specific gravity bottle with distilled water up to the brim and then place the stopper tightly so as to exclude extra water. 
    5.    Dry the exteriors of the bottle with a tissue paper
    6.    Record the weight of (bottle + water) say A
    7.    Similarly, fill the same specific gravity bottle with test sample and record the weight (bottle + sample) say B
    8.    Calculate the specific gravity of solution using the following formula

Materials Required

Sample, reagents, beakers, conical flasks, pestle and mortar, funnels, volumetric flasks, pipettes, weighing balance, spectrophotometer/colorimeter.

Reagents

    1.    2% Metaphosphoric Acid Solution: Weigh 20 g of HPO₃ and dilute to 1 litre in water or 4% oxalic acid.
    2.    Dye Solution: Dissolve 100 mg of 2, 6 Dichlorophenol-indophenol dye (Phenolindo-2,6- dichlorophenol sodium salt, AR, C₁₂H₆Cl₂NNaO₂ 2-3H₂O) and 84 mg of sodium bicarbonate (sodium hydrogen carbonate AR, NaHCO₃) in hot (85-95ºC) distilled water. Cool and make up the vol 100 ml. Filter and dilute 25 ml of the dye to 500 ml with distilled water. 
    3.    Standard Ascorbic Acid: Weigh 50 mg of ascorbic acid (AR) and make up to 50 ml with 2% metaphosphoric acid or 4% Oxalic acid solution (1000 ppm i.e. 1000 µg/ml). Dilute 4 ml of this solution to 100 ml with 2% HPO₃ or 4% oxalic acid. (1ml = 40 µg ascorbic acid).